HVAC Home Air Filter

ABSTRACT

An apparatus and a method are provided for a heating, ventilation, and air conditioning (HVAC) home air filter to remove airborne molecular contaminants and volatile organic compounds (VOCs) from air within residential spaces. The HVAC home air filter comprises a supportive frame having a shape and size suitable to orient the HVAC home air filter within a residential HVAC system. A filter medium is retained within the supportive frame to remove the airborne molecular contaminants and VOCs from air flowing through the residential HVAC system. The filter medium comprises a combination of media layers configured to exhibit a relatively high filtration efficiency and a low air pressure drop across the filter medium. The supportive frame comprises a plurality of elongate sections and corner sections disposed along perimeter edges of the filter medium to support the filter medium within the residential HVAC system so as direct air through the filter medium.

PRIORITY

This application is a continuation of, and claims the benefit of, U.S.patent application Ser. No. 15/207,025, entitled “HVAC Home Air Filter,”filed on Jul. 11, 2016, which is a continuation-in-part of, and claimsthe benefit of, U.S. patent application Ser. No. 14/974,092, entitled“HVAC System Air Filter,” filed on Dec. 18, 2015, which is acontinuation-in-part of, and claims the benefit of, U.S. patentapplication Ser. No. 14/668,772, entitled “Cabin Air Filter,” filed onMar. 25, 2015, the entirety of each of said applications is incorporatedherein by reference.

FIELD

The field of the present disclosure generally relates to filter devices.More particularly, the field of the invention relates to an apparatusand a method for a HVAC system air filter to remove airborne molecularcontaminants and volatile organic compounds from air within interiorbuilding spaces.

BACKGROUND

Heating, ventilation, and air conditioning (HVAC) systems generallyoperate to provide optimal indoor air quality to occupants withininterior building spaces. HVAC systems achieve optimal indoor airquality by conditioning air, removing particle contaminants by way ofventilation and filtration of air, and providing proper buildingpressurization.

While there are many different HVAC system designs and operationalapproaches, and each building design is unique, HVAC systems generallyshare a few basic design elements. For example, outside air (“supplyair”) generally is drawn into a HVAC system of a building through an airintake. Once in the HVAC system, the supply air is filtered to removeparticle contaminants, then heated or cooled, and then circulatedthroughout the building by way of an air distribution system. Many airdistribution systems comprise a return air system configured to draw airfrom interior building spaces and return the air (“return air”) to theHVAC system. The return air is then mixed with supply air and thenfiltered, conditioned, and circulated throughout the building. Oftentimes, a portion of the air circulating within the building may beexhausted to the exterior of the building so as to maintain a desiredbarometric pressure within the building.

As will be appreciated, the effectiveness of the HVAC system to providean optimal indoor air quality depends largely on an ability of an airfilter within the HVAC system to remove particle contaminants from theair within the building. A HVAC system air filter typically comprisesfibrous materials configured to remove solid particulates, such as dust,pollen, mold, and bacteria from the air passing through the HVAC system.A drawback to conventional HVAC system air filters, however, is thathighly effective air filters capable of removing very smallcontaminants, such as airborne molecular contaminants and volatileorganic compounds (VOCs), tend to restrict airflow through the airfilter, thereby making the HVAC system work harder and consume moreenergy.

Another drawback to conventional HVAC system air filters is that dirtyor clogged air filters typically are removed from the HVAC system anddiscarded, and a new HVAC system air filter is then installed. Further,HVAC system air filters may be unnecessarily discarded and replaced inan effort to increase HVAC system airflow and thus decrease operationcosts. Considering that there are millions of buildings with HVACsystems throughout the world, the volume of discarded air filters thatcould be eliminated from landfills is a staggering number. What isneeded, therefore, is a HVAC system air filter that may be periodicallycleaned and reused, and is configured for removing airborne molecularcontaminants and VOCs without obstructing air flow through the HVACsystem.

SUMMARY

An apparatus and a method are provided for a heating, ventilation, andair conditioning (HVAC) home air filter to remove airborne molecularcontaminants and volatile organic compounds (VOCs) from air withinresidential spaces. The HVAC home air filter comprises a supportiveframe having a shape and size suitable to orient the HVAC home airfilter within a residential HVAC system. A filter medium is retainedwithin the supportive frame and configured to remove the airbornemolecular contaminants and VOCs from air flowing through the residentialHVAC system. The filter medium preferably is disposed between a firstscreen and a second screen, at least one of which comprising nylon, toprevent bowing of the filter medium due to air pressure. The filtermedium generally comprises a combination of one or more media layers,each of which having unique filtration properties, such that thecombination of media layers exhibits a relatively high filtrationefficiency and a relatively low air pressure drop across the filtermedium. The supportive frame comprises a plurality of elongate sectionsand corner sections disposed along perimeter edges of the filter mediumand is configured to orient the filter medium within the residentialHVAC system.

In an exemplary embodiment, a heating, ventilation, and air conditioning(HVAC) home air filter to remove airborne molecular contaminants andvolatile organic compounds (VOCs) from air within residential spacescomprises a supportive frame comprising a shape and size suitable fororienting the HVAC home air filter within a residential HVAC system; anda filter medium retained within the supportive frame and is configuredto remove the airborne molecular contaminants and VOCs from air flowingthrough the residential HVAC system.

In another exemplary embodiment, the filter medium is comprised ofpaper, foam, cotton, spun fiberglass, or other known filter materials,woven or non-woven material, synthetic or natural, or any combinationthereof. In another exemplary embodiment, the filter medium is pleated,or otherwise shaped, or contoured so as to increase the surface area forpassing the air stream to be cleaned. In another exemplary embodiment,the filter medium is disposed between a first screen and a secondscreen, at least one of the first screen and the second screencomprising nylon, and wherein the supportive frame comprises a pluralityof elongate sections and corner sections disposed along perimeter edgesof the filter medium and configured to orient the filter medium withinthe residential HVAC system.

In another exemplary embodiment, the filter medium comprises acombination of one or more media layers, each of the one or more medialayers having unique filtration properties, such that the combination ofone or more media layers exhibits a relatively high filtrationefficiency and a relatively low air pressure drop across the filtermedium. In another exemplary embodiment, the filter medium exhibits afiltration efficiency of at least 38% and a basis filtration efficiencyof substantially 43.3%. In another exemplary embodiment, the combinationof one or more media layers comprises a first media layer and a secondmedia, the first media layer comprising a fiber density that isrelatively lower than a fiber density of the second media layer. Inanother exemplary embodiment, the filter medium comprises a fiberdensity that generally increases in a direction of air flow through thefilter medium. In another exemplary embodiment, the filter mediumcomprises a weight ranging between substantially 96.6 grams per squaremeter (gm/m²) and 106.8 gm/m². In another exemplary embodiment, thefilter medium comprises a thickness ranging between substantially 2.54mm and substantially 4.57 mm. In another exemplary embodiment, thefilter medium comprises an air permeability ranging betweensubstantially 2.08 cubic meters of air per second per square meter ofthe filter medium (m³/s-m²) and substantially 2.44 m³/s-m².

In another exemplary embodiment, the filter medium comprises acombination of one or more media layers, each of the one or more medialayers having a unique appearance, the combination of one or more medialayers being configured to exhibit a relatively high filtrationefficiency and a relatively low air pressure drop across the filtermedium, and the unique appearance being configured to indicate apreferred direction of air flow through the filter medium. In anotherexemplary embodiment, the combination of one or more media layerscomprises a first media layer and a second media, the first media layercomprising a gold color and the second media layer comprising a whitecolor, the gold color indicating an air entry side of the filter medium,and the white color which indicating an air exit side of the filtermedium.

In another exemplary embodiment, an electrostatic portion of the filtermedium is configured to electrostatically attract and agglomerateparticle contaminants within the air flowing through the residentialHVAC system. In another exemplary embodiment, the electrostatic portionof the filter medium comprises at least some fibers that are treatedwith a coating of antimicrobial molecules configured to destroymicrobes, the antimicrobial molecules comprising positively chargedmolecules distributed around a circumference of each of the at leastsome fibers and configured to cooperate with polarized fibers within thefilter medium. In another exemplary embodiment, the filter medium isconfigured to electrostatically entrap particle contaminants and releasea fragrance into the air flowing through the residential HVAC system,the filter medium comprising antimicrobial molecules configured todestroy entrapped particle contaminants, the filter medium comprising atleast one substance configured to release the fragrance into air passingthrough the filter medium, wherein the at least one substance is locateddownstream of the antimicrobial molecules so as to avoid destruction ofaromatic molecules by the antimicrobial molecules.

In an exemplary embodiment, a method for cleaning a heating,ventilation, and air conditioning (HVAC) home air filter which isinstalled within a residential HVAC system, the method comprisesremoving the HVAC home air filter from the residential HVAC system;clearing the residential HVAC system of any debris trapped therein;flushing contaminants from a filter medium of the HVAC home air filterby way of a water hose; allowing the water and contaminants to drainfrom the filter medium; and allowing the filter medium to dry.

In another exemplary embodiment, removing the HVAC home air filterfurther comprises disassembling a supportive frame comprising the HVAChome air filter and removing the filter medium therefrom. In anotherexemplary embodiment, flushing contaminants from the filter mediumfurther comprises using a solvent to remove a filter oil compositionfrom the filter medium. In another exemplary embodiment, allowing thefilter medium to dry further comprises applying a filter oil compositionto the filter medium.

In an exemplary embodiment, a heating, ventilation, and air conditioning(HVAC) home air filter to remove airborne molecular contaminants andvolatile organic compounds (VOCs) from air within residential spaces,comprises a filter medium comprising a combination of one or more medialayers disposed between a first screen and a second screen, the filtermedium being configured to remove the airborne molecular contaminantsand VOCs from air flowing through a residential HVAC system of aresidence; and a supportive frame comprising a plurality of elongatesections and corner sections disposed along perimeter edges of thefilter medium and configured to orient the filter medium within theresidential HVAC system.

In another exemplary embodiment, each of the elongate sections andcorner sections comprises a U-shaped cross-sectional shape including anopen side that provides a recess suitable to receive a perimeter edge ofthe filter medium. In another exemplary embodiment, the elongatesections and corner sections are configured to be assembled, such thatthe recess extends along an inside perimeter of the supportive framewhereby the filter medium may be retained within the supportive frame.In another exemplary embodiment, each of the corner sections comprisesat least one folded portion comprising a tab that extends toward aninterior of the recess and configured to slidably retain a correspondingedge of the elongate section. In another exemplary embodiment, each ofthe corner sections comprises a plurality of folded portions thatcooperate to retain the elongate section within the corner section. Inanother exemplary embodiment, the folded portions are configured to gripthe elongate section with a degree of force that allows a practitionerto insert the elongate sections into the corner sections, and therebyassemble the supportive frame. In another exemplary embodiment, thefolded portions are configured to grip the elongate section with adegree of force that provides enough friction to maintain an assembledstate of the supportive frame during operation of the air filter.

In another exemplary embodiment, the elongate sections and the cornersections are configured to have a sliding relationship therebetween soas to facilitate a practitioner adjusting a length and a width of thesupportive frame to accommodate variations in the shape and size of aninterior of the residential HVAC system. In another exemplaryembodiment, the elongate sections and the corner sections are configuredto be adjusted so as to enable a practitioner to tailor the length andwidth of the supportive frame, such that substantially all unfilteredair is directed through the filter medium.

In another exemplary embodiment, the supportive frame comprises a grateconfigured to enclose the filter medium within the supportive framewithout restricting airflow through the filter medium. In anotherexemplary embodiment, at least one of the first screen and the secondscreen is comprised of nylon. In another exemplary embodiment, at leastone of the first and second screens is comprised of a rigid material,such as any of various suitable plastics, metals, and the like.

In another exemplary embodiment, the combination of one or more medialayers is configured to exhibit a relatively high filtration efficiencyand a relatively low air pressure drop across the filter medium. Inanother exemplary embodiment, the combination of one or more medialayers comprises a first media layer and a second media layer, the firstmedia layer comprising a fiber density that is relatively lower than afiber density of the second media layer. In another exemplaryembodiment, the filter medium comprises a fiber density that generallyincreases in a direction of air flow through the filter medium.

In an exemplary embodiment, a method for a heating, ventilation, and airconditioning (HVAC) home air filter to remove airborne molecularcontaminants and volatile organic compounds (VOCs) from air withinresidential spaces, comprises combining one or more filter media layersto form a filter medium to exhibit a relatively high filtrationefficiency and a relatively low air pressure drop across the filtermedium; coupling the filter medium between a first nylon screen and asecond nylon screen so as to resist bowing of the filter medium; andconfiguring a plurality of elongate sections and corner sections to bedisposed along perimeter edges of the filter medium so as to orient thefilter medium within the residential HVAC system.

In another exemplary embodiment, configuring comprises forming aU-shaped cross-sectional shape of the plurality of elongate sections andthe corner sections, such that an open side of the U-shapedcross-sectional shape provides a recess suitable to receive theperimeter edges of the filter medium. In another exemplary embodiment,configuring further comprises forming the plurality of elongate sectionsand corner sections to be assembled, such that the plurality of elongatesections and corner sections comprise a supportive frame and the recessextends along an inside perimeter of the supportive frame whereby thefilter medium may be retained within the supportive frame. In anotherexemplary embodiment, combining comprises pairing a first media layerand a second media layer, the second media layer possessing a fiberdensity that is relatively greater than a fiber density of the firstmedia layer, such that the filter medium comprises an overall fiberdensity that generally increases in a direction of air flow through thefilter medium.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings refer to embodiments of the present disclosure in which:

FIG. 1 illustrates a cross-sectional view of an exemplary useenvironment wherein a HVAC system air filter is incorporated into a HVACsystem of a building, according to the present disclosure;

FIG. 2 illustrates a schematic view of an exemplary embodiment of aresidential HVAC system comprising a HVAC home air filter in accordancewith the present disclosure;

FIG. 3 illustrates an exemplary embodiment of a HVAC home air filter,according to the present disclosure;

FIG. 4 illustrates a close-up perspective view of a corner of the HVAChome air filter of FIG. 3, in accordance with the present disclosure;

FIG. 5 illustrates a cross-sectional view of an exemplary embodiment ofa portion of a composite filter medium configured for entrappingparticle contaminants by way of electrostatic attraction andagglomeration; and

FIG. 6 illustrates cross-sectional views of an exemplary embodiment of apolarized fiber and an unpolarized passive fiber being exposed toparticle contaminants within an air stream flowing from an upstream areato a downstream area.

While the present disclosure is subject to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and will herein be described in detail. Theinvention should be understood to not be limited to the particular formsdisclosed, but on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the present disclosure.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present disclosure. Itwill be apparent, however, to one of ordinary skill in the art that theinvention disclosed herein may be practiced without these specificdetails. In other instances, specific numeric references such as “firstportion,” may be made. However, the specific numeric reference shouldnot be interpreted as a literal sequential order but rather interpretedthat the “first portion” is different than a “second portion.” Thus, thespecific details set forth are merely exemplary. The specific detailsmay be varied from and still be contemplated to be within the spirit andscope of the present disclosure. The term “coupled” is defined asmeaning connected either directly to the component or indirectly to thecomponent through another component. Further, as used herein, the terms“about,” “approximately,” or “substantially” for any numerical values orranges indicate a suitable dimensional tolerance that allows the part orcollection of components to function for its intended purpose asdescribed herein.

In general, the present disclosure describes an apparatus and a methodfor a heating, ventilation, and air conditioning (HVAC) home air filterto remove airborne molecular contaminants and volatile organic compounds(VOCs) from air within residential spaces. The HVAC home air filtercomprises a supportive frame having a shape and size suitable to orientthe HVAC home air filter within a residential HVAC system. A filtermedium is retained within the supportive frame and configured to removethe airborne molecular contaminants and VOCs from air flowing throughthe residential HVAC system. The filter medium generally comprises acombination of one or more media layers configured to exhibit arelatively high filtration efficiency and a relatively low air pressuredrop across the filter medium. The supportive frame comprises aplurality of elongate sections and corner sections disposed alongperimeter edges of the filter medium and is configured to orient thefilter medium within the residential HVAC system, such that air flowingthrough the residential HVAC system is passed through the filter medium.

FIG. 1 illustrates an exemplary use environment 100 wherein an airfilter 104 is incorporated into a HVAC system 108 of a building 112 soas to clean an air stream drawn through the air filter 104. Although thebuilding 112 illustrated in FIG. 1 comprises a multi-story officebuilding, it should be understood that the building 112 may comprise anyof various inhabitable structures, such as residential homes,apartments, condominiums, and the like. After passing through the airfilter 104, the air stream is routed into one or more building spaces116 by way of a supply ductwork 110. Air within the building spaces 116is routed back to the HVAC system 108 by way of a return ductwork 114.It will be appreciated that the building 112 may comprise multiplestories, each of which stores including one or more building spaces 116,as illustrated in FIG. 1, or may comprise a single story building,including but not limited to a detached residential home.

FIG. 2 illustrates a schematic view of an exemplary embodiment of aresidential HVAC system 108 that may be used to clean air withinresidential living spaces 116. The residential HVAC system 108 generallycomprises a fan 120 configured to draw a return air stream 124 from theresidential living spaces 116 through the air filter 104 wherebyairborne molecular contaminants, volatile organic compounds, and otherparticle contaminants are removed from the air stream. Particlecontaminants removed from the return air stream 124 are entrapped in theair filter 104. The fan 120 then pushes a clean air stream 128 throughan air conditioning system 132 and a heater core 136 and then into theresidential living spaces 116. As will be appreciated, the airconditioning system 132 and the heater core 136 facilitate providing aconsistent, comfortable temperature within the residential living spaces116 by respectively cooling and heating the clean air stream 128, asneeded. As further shown in FIG. 2, the return air stream 124 may becombined with an outside air stream 126, as well as with a bypass airstream 130 air stream so as to maintain a desired barometric pressurewithin the residential HVAC system 108 and within the residential livingspaces 116. In some embodiments, an exhaust air stream 134 may befurther incorporated into the residential HVAC system 108 so as tomaintain the desired barometric pressure and to allow entry of theoutside air stream 126.

FIG. 3 illustrates an exemplary embodiment of an air filter 104according to the present disclosure. The air filter 104 generallycomprises a filter medium 144 retained within a supportive frame 148.The supportive frame 148 is configured to orient the air filter 104within the residential HVAC system 108 such that the return air stream124 is directed through the filter medium 144. As such, the supportiveframe 148 comprises a shape and size suitable for supporting the airfilter 104 within the residential HVAC system 108. It will beappreciated that the shape and size of the supportive frame 148 willvary depending upon a make and model of the residential HVAC system 108for which the air filter 104 is intended to be used.

The filter medium 144 provides an area to pass an air stream and entrapparticulates and other contaminates flowing with the air stream. Thefilter medium 144 may be comprised of paper, foam, cotton, spunfiberglass, or other known filter materials, woven or non-wovenmaterial, synthetic or natural, or any combination thereof. The filtermedium 144 may be pleated, or otherwise shaped, or contoured so as toincrease the surface area for passing the air stream to be cleaned.Thus, the length of the filter medium 144 may be greater than the lengthof the air filter 104 generally, due to the pleats, such that thesurface area of the filter medium 144 is greater than the surface areaof the air filter 104.

In some embodiments, the filter medium 144 may be a composite filtermedium comprising one or more media layers, each having uniquefiltration properties such that the combination of media layers exhibitsa relatively high filtration efficiency and a relatively low airpressure drop across the filter medium 144. In the embodimentillustrated in FIGS. 3-4, the filter medium 144 comprises a first medialayer and a second media layer. The first media layer comprises a fiberdensity that is relatively lower than the fiber density of the secondmedia layer. Thus, the filter medium 144 comprises a fiber density thatgenerally increases in the direction of the air flow through the filtermedium. In one embodiment, the filter medium 144 exhibits a filtrationefficiency of at least 38% and a basis filtration efficiency ofsubstantially 43.3%, as measured by way of a TSI Model 8130 automatedfilter tester that utilizes a 0.1 μm count median diameter salt (NaCl)aerosol with a flowrate of substantially 85 liters per minute.

The combination of media layers comprising the filter medium 144generally is lightweight and relatively thin. In one embodiment, thefilter medium 144 comprises a basis weight of substantially 3.0 ouncesper square yard (ounces/yd²) and a weight range between substantially2.85 and 3.15 ounces/yd². In one embodiment, the filter medium comprisesa basis weight of substantially 101.7 grams per square meter (gm/m²),and a weight ranging between substantially 96.6 gm/m² and 106.8 gm/m². Abasis thickness of the filter medium 144 is substantially 0.140 inches,or 3.56 millimeters (mm), and a thickness of the filter medium 144ranges between substantially 0.100 inches (2.54 mm) and 0.180 inches(4.57 mm).

In one embodiment, the filter medium 144 comprises an air permeabilityranging between substantially 410 cubic feet of air per minute persquare foot of the filter medium (cfm) and substantially 480 cfm, andcomprises a basis air permeability of substantially 445 cfm. In oneembodiment, the air permeability of the filter medium 144 ranges betweensubstantially 2.08 cubic meters of air per second per square meter ofthe filter medium (m³/s-m²) and substantially 2.44 m³/s-m², and a basisair permeability of the filter medium 144 is substantially 2.26 m³/s-m².

As will be appreciated, each of the media layers comprising the filtermedium 144 generally may have a unique appearance, due at least in partto the different fiber densities discussed above. It is contemplatedthat, in some embodiments, the unique appearances of the media layersmay indicate a preferred direction of air flow through the filter medium144. For example, in the embodiment illustrated in FIGS. 3-4, the firstmedia layer comprises a gold color and the second media layer comprisesa white color. Thus, a first side of the air filter 104 has the goldcolor, and may indicate an air entry side of the filter, and a secondside of the air filter has the white color which may indicate an airexit side of the filter. The colors of the first and second sides of theair filter 104 may serve to ensure a proper installation of the airfilter into the residential HVAC system 108, such the fiber density ofthe filter medium 144 generally increases in the direction of an airflow through the air filter 104.

The supportive frame 148 may comprise various fastening, or supportive,structures and materials suitably configured for securing the air filter104 within a particular residential HVAC system 108. To this end, in theembodiment illustrated in FIG. 3, the supportive frame 148 comprises aplurality of elongate sections 152 and corner sections 156 disposedalong the perimeter edges of the filter medium 144 and configured tosupport the filter medium 144 within the residential HVAC system 108. Inother embodiments, however, the supportive frame 148 may comprise any ofvarious rigid supports, shapes, and recesses configured to orient theair filter 104 within various makes and models of the residential HVACsystem 108. It should be understood, therefore, that various structures,shapes, and materials incorporated into the supportive frame 148, andthus the air filter 104 as a whole, may vary depending upon theparticular residential HVAC system 108 for which the air filter 104 isintended to be used without detracting from the spirit and scope of thepresent disclosure.

It will be appreciated that the filter medium 144 generally is retainedwithin the supportive frame 148. In the embodiment illustrated in FIGS.3-4, the elongate sections 152 and corner sections 156 comprise aU-shaped cross-sectional shape, the open side of which forms a recess160 suitable to receive the perimeter edges of the filter medium 144.Upon assembling the elongate sections 152 and corner sections 156, asshown in FIGS. 3-4, the recess 160 extends along an inside perimeter ofthe supportive frame 148 thereby retaining the filter medium 144 withinthe supportive frame. As best shown in FIG. 4, the corner section 156comprises folded portions 164 disposed on opposite ends of the cornersection, as well as on opposing sides of the corner section 156. In theillustrated embodiment, each of the folded portions 156 comprises a tabthat is extended toward an interior of the recess 160 and configured toslidably retain an edge of the elongate section 152.

As will be recognized, the folded portions 156 cooperate to retain theelongate sections 152 within the corner section 156, as shown in FIG. 4.It is contemplated that the folded portions 164 grip the elongatesections 152 with a degree of force that allows a practitioner to insertthe elongate sections 152 into the corner sections 156, and therebyassemble the supportive frame 148, as shown in FIG. 3, but providesenough friction to maintain an assembled state of the supportive frame148 during use of the air filter 104. Further, it is envisioned that asliding relationship between the elongate sections 152 and the cornersections 156 generally facilitates adjusting the length and width of thesupportive frame 148 to accommodate variations in the shape and size ofducting within the residential HVAC system 108. For example, it is notuncommon for an air filter that is appropriately sized for a particularresidential HVAC system 108 to allow a small gap of unfiltered air tobypass the filter medium due to variations in the assembly of the HVACsystem. Upon installing the air filter 104, however, the elongatesections 152 and the corner sections 156 may be adjusted to tailor thelength and width of the supportive frame 148, such that substantiallyall unfiltered air is passed through the filter medium 144.

It is contemplated that any of a variety of fasteners or structures maybe implemented so as to retain the filter medium 144 within thesupportive frame 148. In some embodiments, the supportive frame 148 maycomprise a grate, or a similar structure, which encloses the filtermedium 144 within the supportive frame 148 without restricting airflowthrough the filter medium 144. In some embodiments, the filter medium144 may be coupled with a wire support configured to resist bowing ofthe filter medium 144 due to the air stream passing therethrough. Forexample, the filter medium may be disposed between a first screen and asecond screen. In the embodiment illustrated in FIGS. 3-4, the first andsecond screens are comprised of nylon. In other embodiments, however,the first and second screens may be comprised of a rigid material, suchas, by way of non-limiting example, any of various suitable plastics ormetals.

In some embodiments, the supportive frame 148 may be molded directlyonto the edges of the filter medium 144 so as to retain the filtermedium within the frame. In some embodiments, the supportive frame 148may be molded to the wire supports of the filter medium 144. Forexample, in those certain embodiments wherein the filter medium 144 isdisposed between the first screen and the second screen, the supportiveframe 148 may be molded onto the first and second screens to retain thefilter medium 144 within the supportive frame 148. Further, in someembodiments, the supportive frame 148 may comprise a crimped portionthat folds onto and retains the first and second screens and the filtermedium 144 within the supportive frame. It should be recognized,however, that fastening the filter medium 144 to the supportive frame148 renders the filter medium 144 irremovable from the supportive frame148. Although the filter medium 144 may be irremovable from the frame insome embodiments, it should be understood that in a preferredembodiment, the filter medium 144 is removable from the supportive frame148, as described herein, without deviating from the scope of thepresent disclosure.

It is contemplated that a practitioner may periodically clean the filtermedium 144 rather than replacing the air filter 104, as is typicallydone with conventional air filter systems. It is envisioned that the airfilter 104 may be removed from the residential HVAC system 108, and anytrapped debris may then be removed from the residential HVAC system 108.The elongate sections 152 and the corner sections 156 may bedisassembled so as to release the filter medium 144 from the supportiveframe 148 and then a water hose may be used to flush contaminants fromthe filter medium 144, thereby leaving the filter clean and ready forreuse. In some embodiments, wherein the filter medium 144 comprises afilter oil composition, a solvent may be used to remove the filter oilfrom the filter medium 144. Once the filter medium 144 has beensufficiently dried, a suitably formulated filter oil composition may beapplied and allowed to wick into the filter medium 144. The elongatesections 152 and corner sections 156 may then be assembled onto thefilter medium 144, as described above, and the air filter 104 may bereinstalled into the residential HVAC system 108. Various other cleaningmethods will be apparent to those skilled in the art without deviatingfrom the spirit and scope of the present disclosure.

In some embodiments, wherein the filter medium 144 comprises the filteroil composition, the filter medium 144 may comprise at least a cottongauze portion including 4 to 6 layers of cotton gauze disposed betweentwo epoxy-coated aluminum wire screens. As described above, however, thewire screens may be comprised of nylon, or other suitable thermoplasticmaterial. The cotton may be advantageously treated with theabove-mentioned filter oil composition so as to cause tackinessthroughout microscopic strands comprising the filter medium 144. Thenature of the cotton allows high volumes of airflow, and when combinedwith the tackiness of the filter oil composition creates a powerfulfiltering medium which ensures a high degree of air filtration.

During operation of the residential HVAC system 108, contaminantparticles cling to the fibers within the volume of the filter medium 144and become part of the filtering medium 144, a process referred to as“depth loading.” It will be appreciated that depth loading allows theair filter 104 to capture and retain significantly more contaminants perunit of area than conventional air filters. Contaminant particles arestopped by the layers of cotton gauze and held in suspension by thefilter oil composition, and thus the contaminants collected on thesurface of the filter medium 144 have little effect on air flow duringmuch of the service life of the air filter 104. Moreover, as the filtermedium 144 collects an increasing volume of contaminants and debris, anadditional degree of filtering action begins to take place as the returnair stream 124 first passes through the trapped contaminants on thesurface of the filter medium 144 before passing through deeper layerswithin the filter medium 144. In essence, the trapped contaminants beginto operate as an additional filter material which precedes the filtermedium 144. Thus, the air filter 104 continues to exhibit a high degreeof air flow and filtration throughout the service life of the filter,thereby reducing operating costs of the residential HVAC system 108.

As will be appreciated, treating the filter medium 144 with the filteroil composition generally enables the filter medium 144 to capturecontaminants by way of interception, whereby contaminants, such as dirtparticles, traveling with the return air stream 124 directly contact thefibers comprising the filter medium 144 and are then held in place bythe filter oil composition. Larger or heavier particles generally arecaptured by way of impaction, whereby inertia or momentum of theparticles causes them to deviate from the path of the return air stream124 through the filter medium 144, and instead the particles runstraight into the fibers and are captured by the filter oil composition.

Particle contaminants having very small sizes may be captured by way ofdiffusion. As will be appreciated, small particles are highly affectedby forces within the return air stream 124 through the filter medium144. Forces due to velocity changes, pressure changes, and turbulencecaused by other particles, as well as interaction with air molecules,generally causes the small particles to follow random, chaotic flowpaths through the filter medium 144. Consequently, the small particlesdo not follow the return air stream 124, and their erratic motion causesthem to collide with the fibers comprising the filter medium 144 andremain captured by the filter oil composition. Diffusion and the filteroil composition enable the air filter 104 to capture particlecontaminants having sizes that are much smaller than the openingsbetween the fibers comprising the filter medium 144. Furthermore, thefilter oil composition enables the air filter 104 to capturecontaminants throughout the volume of the filter medium 144, rather thanonly on the surface of the filter as is common with conventional airfilters. The multiple layers of cotton fibers comprising the filtermedium 144 coupled with the tackiness provided by the filter oilcomposition provide many levels of contaminant retention, therebyenabling the air filter 104 to hold significantly more contaminants perunit of area of the filter medium 144 than is possible with conventionalair filters.

As will be appreciated, the filter oil composition of the presentdisclosure is critical to the enhanced air flow and filtrationproperties of the air filter 104. In some embodiments, the filter oilcomposition comprises an oil formulation which is non-reactive, has anexcellent oxidation stability, possesses good thermal stability, andretains a suitable viscosity at normal operating temperatures of theresidential HVAC system 108. In some embodiments, the filter oilcomposition may be a mixture of oils and colored dyes suitable forenhancing the tackiness of the filter medium 144, such as by way ofnon-limiting example, paraffinic oils, polyalphaolefins, and the like.In some embodiments, the filter oil composition comprises a mixture of96.74% paraffinic oil by volume, 3.20% polyalphaolefin (PAO) by volume,and 0.06% colored dye by volume. In some embodiments, the filter oilcomposition has a viscosity at 100 degrees-C ranging betweensubstantially 7.2 and 7.6 centistokes (cSTs). It is to be understoodthat the particular oils and dyes, as well as their colors andviscosities, as well as their individual concentrations within thefilter oil composition may be altered without deviating from the spiritand the scope of the present disclosure.

In some embodiments, the layers of cotton gauze treated with the filteroil composition may be coupled with portions of the filter medium 144wherein other filtration mechanisms are used, thereby forming acomposite filter medium 144 capable of removing airborne molecularcontaminants and VOCs from the return air stream 124. In someembodiments, the composite filter medium 144 may be comprised of acotton gauze portion, as described herein, and an electrostatic portion.

FIG. 5 illustrates a cross-sectional view of an electrostatic portion168 of the composite filter medium 144 which may be disposed downstreamof the cotton gauze portion and configured for utilizing electrostaticattraction and agglomeration to entrap particle contaminants. Theembodiment of FIG. 5 may be configured to entrap contaminant particlespossessing diameters on the order of substantially 0.3 microns. Theelectrostatic portion 168 of the composite filter medium 144 comprises acentral screen 172 configured to be electrically charged to a highelectrostatic potential. In some embodiments, the central screen 172 maybe positively charged to substantially 7,000 VDC. The central screen 172may be covered on each side by at least one layer of fibers 176 capableof being electrically polarized. As shown in FIG. 5, each of the atleast one layer of polarizable fibers 176 may be covered by an exteriorgrounded wire screen 180. It will be appreciated that upon positivelycharging the central screen 172, the polarizable fibers 176 operate topolarize incoming particle contaminants within the return air stream124, thereby causing the contaminants to become electrostaticallyattracted to the polarizable fibers 176. Thus, particle contaminantsthat would otherwise avoid directly colliding with the fibers 176 areelectrostatically captured and entrapped within the filter medium 144.

FIG. 6 illustrates cross-sectional views of a polarized fiber 184 and anunpolarized passive fiber 188 being exposed to particle contaminantswithin an air stream 192 that flows from an upstream area 196 to adownstream area 200. As shown in FIG. 6, electrostatic attractionbetween the particle contaminants and the polarized fiber 184 uniformlydistributes the contaminants on the surface of the polarized fiber 184.The electrostatic attraction ensures the capture of contaminants thatwould otherwise pass by the fiber 184 without a direct collision andcontinue flowing to the downstream area 200. Unlike the polarized fiber184, the unpolarized passive fiber 188 relies solely upon directcollisions between the particle contaminants and the fiber, thusallowing non-colliding contaminants to continue flowing to thedownstream area 200.

As further illustrated in FIG. 6, the contaminants that collide with thepassive fiber 188 tend to accumulate on an upstream side of the passivefiber 188. It will be appreciated that as the accumulation ofcontaminants on the upstream side of the passive fiber 188 grows, theair stream 192 becomes proportionally restricted. Thus, filter mediacomprising unpolarized passive fibers 188 are prone to clogging andgreater loading than generally occurs with filter media comprisingpolarized fibers 184. Experimental testing to determine a relationshipbetween fine dust loading and a consequent drop in pressure across eachof several air filter devices has clearly demonstrated that filter mediacomprising polarized fibers 184 entrap more contaminants with a lowerpressure drop across the filter than is otherwise possible withconventional filter media comprising only unpolarized passive fibers188.

In some embodiments, at least some of the fibers comprising thecomposite filter medium 144 may be treated with a coating ofantimicrobial molecules configured to destroy microbes on contact.Preferably, the coating of antimicrobial molecules surroundssubstantially the entire circumference of each fiber strand that istreated. In some embodiments, the antimicrobial molecules may comprisepositively charged molecules that are configured to cooperate with thepolarized fibers 176 of the composite filter medium 144. It iscontemplated that since many microbes and VOCs are negatively charged,incorporating the antimicrobial molecules into the composite filtermedium 144 may electrostatically capture the particle contaminants,thereby enabling the air filter 104 to remove particles from the returnair stream 124 as small as 0.001 microns in diameter, or smaller, suchas many odors, irritants, toxic compounds, and the like.

In some embodiments, fibrous materials comprising a portion of thecomposite filter medium 144 may comprise at least one substanceconfigured to release a fragrance into air passing through the compositefilter medium. Thus, in some embodiments, the air filter 104 may beconfigured to introduce a desired aroma into the residential livingspaces 116. It is contemplated that various HVAC home air filters 104may comprise different fragrances, thereby enabling a user to select theair filter 104 according to a desired aroma. In some embodiments, aparticular scent or aroma may be distributed through the residentialHVAC system 108 into the residential living spaces 116 so as to providean aroma therapy by way of the air filter 104.

In some embodiments, the substances configured to release a fragrancemay be incorporated into the composite filter medium 144 comprising theantimicrobial molecules. Thus, in some embodiments, the composite filtermedium 144 may utilize treated cotton gauze and electrostatic attractionto entrap particle contaminants while simultaneously releasing an aromainto the residential living spaces 116. It will be appreciated, however,that the substances for releasing a fragrance preferably are locatedwithin the composite filter medium 144 downstream of the antimicrobialmolecules so as to avoid destruction of aromatic molecules by theantimicrobial molecules.

It is contemplated that the fragrance may be any natural substance,synthetic material, (incorporating aldehydes, ketones, esters, and otherchemical constituents), or combinations thereof which is known in theart and suitable for use in candles for imparting an odor, aroma, orfragrance. In some embodiments, suitable natural and syntheticfragrance/flavor substances may include those compiled by the U.S. Foodand Drug Administration in Title 21 of the Code of Federal Regulations,Sections 172.510 and 172.515 respectively. In some embodiments, suitablefragrances may comprise spice oil, flower oil, fruit oil, and the like.In some embodiments, suitable fragrances may comprise fragrancecomponents, such as for example benzaldehydes, phenols, cinnamicaldehydes and esters, octadienes, dienes, cyclohexadienes, terpenes, andthe like. Further details regarding dispersion of aromas by way of airfilters and fragrance compositions are disclosed in U.S. patentapplication Ser. No. 10/544,157, entitled “Vehicle cabin air filterfreshener,” filed on Aug. 13, 2003, the entirety of each of which isincorporated herein by reference.

It should be understood that the air filter 104 is not limited solely totreating air within buildings and detached residential homes, but rathermay be used for vehicle passenger cabins wherein passengers, drivers, aswell as occupants reside, such as by way of non-limiting example,automobiles, trucks, recreational vehicles, buses, earthmoving equipmentand tractors with enclosed cabins, crane operator cabins, various cargomoving vehicles, locomotives, rail passenger cars, airplanes,helicopters, ship cabins, airship cabins, and the like. Moreover, theair filter 104 may be incorporated into HVAC systems other than asillustrated in FIG. 1, such as by way of non-limiting example, centralHVAC systems, rooftop HVAC systems, wall-mounted HVAC systems, as wellas portable HVAC systems, and the like.

While the invention has been described in terms of particular variationsand illustrative figures, those of ordinary skill in the art willrecognize that the invention is not limited to the variations or figuresdescribed. In addition, where methods and steps described above indicatecertain events occurring in certain order, those of ordinary skill inthe art will recognize that the ordering of certain steps may bemodified and that such modifications are in accordance with thevariations of the invention. Additionally, certain of the steps may beperformed concurrently in a parallel process when possible, as well asperformed sequentially as described above. To the extent there arevariations of the invention, which are within the spirit of thedisclosure or equivalent to the inventions found in the claims, it isthe intent that this patent will cover those variations as well.Therefore, the present disclosure is to be understood as not limited bythe specific embodiments described herein, but only by scope of theappended claims.

What is claimed is:
 1. A heating, ventilation, and air conditioning(HVAC) home air filter to remove airborne molecular contaminants andvolatile organic compounds (VOCs) from air within residential spaces,comprising: a filter medium comprising a combination of one or moremedia layers disposed between a first screen and a second screen, thefilter medium being configured to remove the airborne molecularcontaminants and VOCs from air flowing through a residential HVAC systemof a residence; and a supportive frame comprising a plurality ofelongate sections and corner sections disposed along perimeter edges ofthe filter medium and configured to orient the filter medium within theresidential HVAC system.
 2. The HVAC home air filter of claim 1, whereineach of the elongate sections and corner sections comprises a U-shapedcross-sectional shape including an open side that provides a recesssuitable to receive a perimeter edge of the filter medium.
 3. The HVAChome air filter of claim 2, wherein the elongate sections and cornersections are configured to be assembled, such that the recess extendsalong an inside perimeter of the supportive frame whereby the filtermedium may be retained within the supportive frame.
 4. The HVAC home airfilter of claim 2, wherein each of the corner sections comprises atleast one folded portion comprising a tab that extends toward aninterior of the recess and configured to slidably retain a correspondingedge of the elongate section.
 5. The HVAC home air filter of claim 2,wherein each of the corner sections comprises a plurality of foldedportions that cooperate to retain the elongate section within the cornersection.
 6. The HVAC home air filter of claim 5, wherein the foldedportions are configured to grip the elongate section with a degree offorce that allows a practitioner to insert the elongate sections intothe corner sections, and thereby assemble the supportive frame.
 7. TheHVAC home air filter of claim 6, wherein the folded portions areconfigured to grip the elongate section with a degree of force thatprovides enough friction to maintain an assembled state of thesupportive frame during operation of the air filter.
 8. The HVAC homeair filter of claim 1, wherein the elongate sections and the cornersections are configured to have a sliding relationship therebetween soas to facilitate a practitioner adjusting a length and a width of thesupportive frame to accommodate variations in the shape and size of aninterior of the residential HVAC system.
 9. The HVAC home air filter ofclaim 1, wherein the elongate sections and the corner sections areconfigured to be adjusted so as to enable a practitioner to tailor thelength and width of the supportive frame, such that substantially allunfiltered air is directed through the filter medium.
 10. The HVAC homeair filter of claim 1, wherein the supportive frame comprises a grateconfigured to enclose the filter medium within the supportive framewithout restricting airflow through the filter medium.
 11. The HVAC homeair filter of claim 1, wherein at least one of the first screen and thesecond screen is comprised of nylon.
 12. The HVAC home air filter ofclaim 11, wherein at least one of the first and second screens iscomprised of a rigid material, such as any of various suitable plastics,metals, and the like.
 13. The HVAC home air filter of claim 1, whereinthe combination of one or more media layers is configured to exhibit arelatively high filtration efficiency and a relatively low air pressuredrop across the filter medium.
 14. The HVAC home air filter of claim 13,wherein the combination of one or more media layers comprises a firstmedia layer and a second media layer, the first media layer comprising afiber density that is relatively lower than a fiber density of thesecond media layer.
 15. The HVAC home air filter of claim 13, whereinthe filter medium comprises a fiber density that generally increases ina direction of air flow through the filter medium.
 16. A method for aheating, ventilation, and air conditioning (HVAC) home air filter toremove airborne molecular contaminants and volatile organic compounds(VOCs) from air within residential spaces, comprising: combining one ormore filter media layers to form a filter medium to exhibit a relativelyhigh filtration efficiency and a relatively low air pressure drop acrossthe filter medium; coupling the filter medium between a first nylonscreen and a second nylon screen so as to resist bowing of the filtermedium; and configuring a plurality of elongate sections and cornersections to be disposed along perimeter edges of the filter medium so asto orient the filter medium within the residential HVAC system.
 17. Themethod of claim 16, wherein configuring comprises forming a U-shapedcross-sectional shape of the plurality of elongate sections and thecorner sections, such that an open side of the U-shaped cross-sectionalshape provides a recess suitable to receive the perimeter edges of thefilter medium.
 18. The method of claim 17, wherein configuring furthercomprises forming the plurality of elongate sections and corner sectionsto be assembled, such that the plurality of elongate sections and cornersections comprise a supportive frame and the recess extends along aninside perimeter of the supportive frame whereby the filter medium maybe retained within the supportive frame.
 19. The method of claim 16,wherein combining comprises pairing a first media layer and a secondmedia layer, the second media layer possessing a fiber density that isrelatively greater than a fiber density of the first media layer, suchthat the filter medium comprises an overall fiber density that generallyincreases in a direction of air flow through the filter medium.